% Licensed under the Apache License, Version 2.0 (the "License"); you may not
% use this file except in compliance with the License.  You may obtain a copy of
% the License at
%
%   http://www.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
% License for the specific language governing permissions and limitations under
% the License.

-module(couch_httpd_misc_handlers).

-export([handle_welcome_req/2,handle_favicon_req/2,handle_utils_dir_req/2,
    handle_all_dbs_req/1,handle_replicate_req/1,handle_restart_req/1,
    handle_uuids_req/1,handle_config_req/1,
    handle_task_status_req/1]).
    
-export([increment_update_seq_req/2]).


-include("couch_db.hrl").

-import(couch_httpd,
    [send_json/2,send_json/3,send_json/4,send_method_not_allowed/2,
    start_json_response/2,send_chunk/2,end_json_response/1,
    start_chunked_response/3, send_error/4]).

% httpd global handlers

handle_welcome_req(#httpd{method='GET'}=Req, WelcomeMessage) ->
    send_json(Req, {[
        {couchdb, WelcomeMessage},
        {version, list_to_binary(couch_server:get_version())}
    ]});
handle_welcome_req(Req, _) ->
    send_method_not_allowed(Req, "GET,HEAD").

handle_favicon_req(#httpd{method='GET'}=Req, DocumentRoot) ->
    couch_httpd:serve_file(Req, "favicon.ico", DocumentRoot);
handle_favicon_req(Req, _) ->
    send_method_not_allowed(Req, "GET,HEAD").
    
handle_utils_dir_req(#httpd{method='GET'}=Req, DocumentRoot) ->
    "/" ++ UrlPath = couch_httpd:path(Req),
    case couch_httpd:partition(UrlPath) of
    {_ActionKey, "/", RelativePath} ->
        % GET /_utils/path or GET /_utils/
        couch_httpd:serve_file(Req, RelativePath, DocumentRoot);
    {_ActionKey, "", _RelativePath} ->
        % GET /_utils
        couch_httpd:send_redirect(Req, "/_utils/")
    end;
handle_utils_dir_req(Req, _) ->
    send_method_not_allowed(Req, "GET,HEAD").


handle_all_dbs_req(#httpd{method='GET'}=Req) ->
    {ok, DbNames} = couch_server:all_databases(),
    send_json(Req, DbNames);
handle_all_dbs_req(Req) ->
    send_method_not_allowed(Req, "GET,HEAD").


handle_task_status_req(#httpd{method='GET'}=Req) ->
    ok = couch_httpd:verify_is_server_admin(Req),
    % convert the list of prop lists to a list of json objects
    send_json(Req, [{Props} || Props <- couch_task_status:all()]);
handle_task_status_req(Req) ->
    send_method_not_allowed(Req, "GET,HEAD").


handle_replicate_req(#httpd{user_ctx=UserCtx,method='POST'}=Req) ->
    {Props} = couch_httpd:json_body(Req),
    Source = proplists:get_value(<<"source">>, Props),
    Target = proplists:get_value(<<"target">>, Props),
    
    {SrcOpts} = proplists:get_value(<<"source_options">>, Props, {[]}),
    {SrcHeadersBinary} = proplists:get_value(<<"headers">>, SrcOpts, {[]}),
    SrcHeaders = [{?b2l(K),(V)} || {K,V} <- SrcHeadersBinary],
    
    {TgtOpts} = proplists:get_value(<<"target_options">>, Props, {[]}),
    {TgtHeadersBinary} = proplists:get_value(<<"headers">>, TgtOpts, {[]}),
    TgtHeaders = [{?b2l(K),(V)} || {K,V} <- TgtHeadersBinary],
    
    {Options} = proplists:get_value(<<"options">>, Props, {[]}),
    Options2 = [{source_options,
                    [{headers, SrcHeaders},
                    {user_ctx, UserCtx}]},
                {target_options,
                    [{headers, TgtHeaders},
                    {user_ctx, UserCtx}]}
                | Options],
    case couch_rep:replicate(Source, Target, Options2) of
        {ok, {JsonResults}} ->
            send_json(Req, {[{ok, true} | JsonResults]});
        {error, {Type, Details}} ->
            send_json(Req, 500, {[{error, Type}, {reason, Details}]});
        {error, Reason} ->
            send_json(Req, 500, {[{error, Reason}]})
    end;
handle_replicate_req(Req) ->
    send_method_not_allowed(Req, "POST").


handle_restart_req(#httpd{method='POST'}=Req) ->
    ok = couch_httpd:verify_is_server_admin(Req),
    couch_server_sup:restart_core_server(),
    send_json(Req, 200, {[{ok, true}]});
handle_restart_req(Req) ->
    send_method_not_allowed(Req, "POST").


handle_uuids_req(#httpd{method='GET'}=Req) ->
    Count = list_to_integer(couch_httpd:qs_value(Req, "count", "1")),
    CacheBustingHeaders = [{"Date", httpd_util:rfc1123_date()},
                           {"Cache-Control", "no-cache"},
                           {"Expires", "Fri, 01 Jan 1990 00:00:00 GMT"},  % Past date, ON PURPOSE!
                           {"Pragma", "no-cache"}],
    % generate the uuids
    UUIDs = [ couch_util:new_uuid() || _ <- lists:seq(1,Count)],
    % send a JSON response
    send_json(Req, 200, CacheBustingHeaders, {[{<<"uuids">>, UUIDs}]});
handle_uuids_req(Req) ->
    send_method_not_allowed(Req, "GET").


% Config request handler

    
% GET /_config/
% GET /_config
handle_config_req(#httpd{method='GET', path_parts=[_]}=Req) ->
    ok = couch_httpd:verify_is_server_admin(Req),
    Grouped = lists:foldl(fun({{Section, Key}, Value}, Acc) ->
        case dict:is_key(Section, Acc) of
        true ->
            dict:append(Section, {list_to_binary(Key), list_to_binary(Value)}, Acc);
        false ->
            dict:store(Section, [{list_to_binary(Key), list_to_binary(Value)}], Acc)
        end
    end, dict:new(), couch_config:all()),
    KVs = dict:fold(fun(Section, Values, Acc) ->
        [{list_to_binary(Section), {Values}} | Acc]
    end, [], Grouped),
    send_json(Req, 200, {KVs});
% GET /_config/Section
handle_config_req(#httpd{method='GET', path_parts=[_,Section]}=Req) ->
    ok = couch_httpd:verify_is_server_admin(Req),
    KVs = [{list_to_binary(Key), list_to_binary(Value)}
            || {Key, Value} <- couch_config:get(Section)],
    send_json(Req, 200, {KVs});
% PUT /_config/Section/Key
% "value"
handle_config_req(#httpd{method='PUT', path_parts=[_, Section, Key]}=Req) ->
    ok = couch_httpd:verify_is_server_admin(Req),
    Value = couch_httpd:json_body(Req),
    Persist = couch_httpd:header_value(Req, "X-Couch-Persist") /= "false",
    OldValue = couch_config:get(Section, Key, ""),
    ok = couch_config:set(Section, Key, ?b2l(Value), Persist),
    send_json(Req, 200, list_to_binary(OldValue));
% GET /_config/Section/Key
handle_config_req(#httpd{method='GET', path_parts=[_, Section, Key]}=Req) ->
    ok = couch_httpd:verify_is_server_admin(Req),
    case couch_config:get(Section, Key, null) of
    null ->
        throw({not_found, unknown_config_value});
    Value ->
        send_json(Req, 200, list_to_binary(Value))
    end;
% DELETE /_config/Section/Key
handle_config_req(#httpd{method='DELETE',path_parts=[_,Section,Key]}=Req) ->
    ok = couch_httpd:verify_is_server_admin(Req),
    case couch_config:get(Section, Key, null) of
    null ->
        throw({not_found, unknown_config_value});
    OldValue ->
        couch_config:delete(Section, Key),
        send_json(Req, 200, list_to_binary(OldValue))
    end;
handle_config_req(Req) ->
    send_method_not_allowed(Req, "GET,PUT,DELETE").


% httpd db handlers

increment_update_seq_req(#httpd{method='POST'}=Req, Db) ->
    {ok, NewSeq} = couch_db:increment_update_seq(Db),
    send_json(Req, {[{ok, true},
        {update_seq, NewSeq}
    ]});
increment_update_seq_req(Req, _Db) ->
    send_method_not_allowed(Req, "POST").